Sink Holes and Fossilised Remains

At http://news.yahoo.com/500-old-traces-monster-hawaii-tsunami-discovered-1… … it is claimed an earthquake in Alaska was responsible in generating a tsunami wave that struck Hawaii in the 15th century AD. That s the main thrust of the news story but caught my eye is they declared a tsunami wave after investigating a sink hole 328 feet beyond the shoreline and 23 feet above sea level. It was choked with marine debris – including large quantities of corals and shells dredged up from the foreshore. However, when researchers explore caves from the Pleistocene era and earlier and come across large quantities of mixed up broken bones of animals they do not suggest a tsunami wave was involved – do they? Well, one supposes that is because the caves are often found well inland, miles from the seaside. You would have to envisage walls of water as the ocean emptied itself across the continental margins – quite unlike a tsunami prompted by a large earthquake on the other side of the ocean basin.